JPH08106166A - Image holding member, image forming method and device unit - Google Patents

Abstract

PURPOSE: To improve wear resistance and to obtain excellent mechanical characteristics and electric characteristics by incorporating a polyester resin having a specified structural unit into the surface layer. CONSTITUTION: This image holding member has plural resin layers on a conductive supporting body. The surface layer contains a polyester resin having the structural unit expressed by formula. In formula, R1 is a 2-4C alkylene group and R2 , R3 , R4 , R5 are hydrogen atoms or 1-4C alkyl groups. The mol.wt. of this polyester resin is preferably controlled to such a mol.wt. that the limiting viscosity of the resin measured in a mixture soln. of 60wt.% phenol and 40wt.% 1,1,2,2-tetrachloroethane at 20 deg.C is >=0.3. More preferably, the mol.wt. ranges from 0.3 to 1.0. If it exceeds 1.0, the viscosity of the coating liquid is too high, which makes controlling of the film thickness difficult.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image holding member using a resin having a specific structure, and more particularly to an image holding member having excellent surface lubricity and durability. The present invention also provides
The present invention relates to an image forming method and an apparatus unit having the above image holding member.

[0002]

2. Description of the Related Art An electrophotographic photoreceptor is a typical example of an image holding member. In recent years, as the electrophotographic photoreceptor, one using an organic light-guiding material is excellent in terms of pollution-free property, high productivity, easiness of material design, and future potential, so that many are proposed, It has been put to practical use. Needless to say, these electrophotographic photoreceptors are required to have various characteristics such as electrical, mechanical, and optical characteristics according to the electrophotographic process to be applied. Particularly, in the case of a photoreceptor that is repeatedly used, electrical and mechanical external forces such as corona charging, image exposure, toner development, transfer to paper and cleaning treatment are directly applied to the surface of the photoreceptor, so durability against them is improved. Required.

Specifically, deterioration of characteristics due to ozone generated at the time of corona charging, that is, sensitivity decrease, potential decrease and residual potential increase, and abrasion of the surface caused by rubbing of the photoreceptor surface during transfer or cleaning, Durability against scratches is required.

The surface of the photoreceptor is generally a very thin resin layer, and the characteristics of the resin used for improving the performance required for the photoreceptor are one of the very important requirements. A polycarbonate resin having bisphenol A as a skeleton has been conventionally used as a resin satisfying the above conditions. However, this resin more than fully satisfies all the properties required for a resin for an electrophotographic photoreceptor. It wasn't. For example, bisphenol A-type polycarbonate resin has relatively high crystallinity, so it easily gels in a solution dissolved in a solvent. When an electrophotographic photosensitive member is prepared using this resin, good electrophotographic characteristics may not be obtained, There were times when productivity fell.

Also, these resin layers have a weak resistance to rubbing due to an elastic blade usually used as a cleaning means and a transfer material (for example, paper) at the time of transfer, and there is a problem that the surface is easily worn.

As a means for solving these problems, it is known to introduce various components into the polycarbonate resin structure to lower the crystallinity and improve the liquid storage stability.
In particular, bisphenol Z type polycarbonate resin
60-172045), it is known to improve the mechanical properties of electrophotographic photoreceptors or the properties of coating liquids, but with the recent demand for faster and smaller electrophotographic processes. There is a demand for an electrophotographic photosensitive member that is more excellent in these characteristics.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems that an image holding member using a polycarbonate resin as a surface layer has in the past and to improve abrasion resistance to provide excellent mechanical properties. An object of the present invention is to provide an image holding member having improved characteristics and electrical characteristics, and further storage stability of a coating liquid, and having excellent image forming characteristics and high productivity, an image forming method and an apparatus unit having the image holding member. .

[0008]

The above object of the present invention has been achieved by the following constitution.

1. An image holding member having a plurality of resin layers on a conductive support, wherein the surface layer contains a polyester resin having a structural unit represented by the following general formula (1).

[0010]

Embedded image

(R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ , R ₄ and R ₅ are hydrogen atoms and 1 to 1 carbon atoms.
4 represents an alkyl group. ) 2. The polyester resin is obtained by a condensation reaction of an aromatic dicarboxylic acid or its diester derivative, an aliphatic glycol having 2 to 4 carbon atoms, and a dihydroxy compound represented by the following general formula (2), and the general formula (2) 2. The image holding member as described in 1 above, wherein the constitutional unit derived from the dihydroxy compound represented by is a polyester resin containing 5 mol% or more in the total glycol component of the polyester resin.

[0012]

[Chemical 4]

(R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ , R ₄ and R ₅ are hydrogen atoms, and 1 to 1 carbon atoms.
4 represents an alkyl group. ) 3. 2. The image holding member according to 1 above, wherein the plurality of resin layers are composed of at least two layers of an undercoat layer, an intermediate layer, a plurality of photosensitive layers, and a protective layer.

4. The above-mentioned 1, which has at least a charge-generating layer on a conductive support and a charge-transporting layer composed of a plurality of layers thereon, and the uppermost layer of the charge-transporting layer is a surface layer of the image holding member.
The image holding member according to 2 or 3.

5. A step of forming an electrostatic latent image on an image holding member in which a polyester resin having a constitutional unit represented by the general formula (1) is contained in a surface layer on a conductive support; An image forming method comprising: a developing step for developing a visible image, a transferring step for transferring a visualized toner image onto a recording material, and a step for cleaning the toner remaining on the image holding member after the transferring.

6. In an apparatus unit having an image holding member, a charging member, a developing means and a cleaning means, the image holding member is the image holding member according to claim 1, wherein the image holding member, the charging means, the developing means and the cleaning means are provided. A device unit that is integrally supported and is removable from the device body.

The molecular weight of the polyester resin of the present invention may be in any range as long as a suitable coating film can be obtained when forming a coating liquid, but the mechanical properties of the coating film are 60% by weight of phenol. In a mixed solution of 40% by weight of 1,1,2,2-tetrachloroethane, a molecular weight at which the intrinsic viscosity measured at 20 ° C. is 0.3 or more is preferable. The range of 0.3 to 1.0 is more preferable. If it exceeds 1.0, the viscosity of the coating solution becomes too high, which makes it difficult to control the film thickness.

The polyester resin of the present invention can be synthesized, for example, by the method described in JP-A-6-49186. That is, from an aromatic dicarboxylic acid or its diester derivative, a dihydroxy compound represented by the following general formula (2) and an aliphatic glycol having 2 to 4 carbon atoms,
For example, it can be produced by selecting an appropriate method from known methods such as a transesterification method, a melt polymerization method such as a direct polymerization method, a solution polymerization method, and an interfacial polymerization method.

[0019]

Embedded image

(In the formula, R ₁ represents an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ , R ₄ and R ₅ represent a hydrogen atom and an alkyl group having 1 to 4 carbon atoms.) The present invention The dihydroxy compound represented by the general formula (2) used for is 9,9-bis- (4-hydroxyethoxyphenyl)-
Fluorene, 9,9-bis- (4-hydroxypropoxyphenyl) -fluorene, 9,9-bis- (4-hydroxybutoxyphenyl) -fluorene, etc., but especially 9,9-bis- (4-hydroxyethoxy) Phenyl) -fluorene is preferred.

9,9-bis- (4-hydroxyethoxyphenyl) -fluorene is, for example, 9,9-bis- (4-hydroxyphenyl) -fluorene with ethylene oxide (hereinafter, EO).
Is obtained by adding.

A 2EO adduct (9,9-bis- (4-hydroxyethoxyphenyl) -fluorene) or 3EO adduct in which one molecule of ethylene oxide is added to each hydroxyl group of phenol,
A 4EO adduct and the like can also be used.

The dihydroxy component in the polyester resin represented by the general formula (1) of the present invention has a constitutional unit derived from the dihydroxy compound represented by the general formula (2) in all the glycol components in the resin. It is preferably contained at 5 mol% or more. When this is less than 5 mol%, the resin obtained is relatively easy to crystallize and the solvent solubility is lowered,
This tends to cause deterioration of the physical properties of the film as an electrophotographic photoreceptor.

In the present invention, as the aliphatic glycol, ethylene glycol, 1,3-propanediol, 1,
2-Propanediol and 1,3-butanediol are used, but among them, ethylene glycol and 1,4-butanediol are preferable, and ethylene glycol is particularly preferable.

In the present invention, as the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid and the like are used, and terephthalic acid is particularly preferably used.

Typical synthetic examples of the polyester resin of the present invention will be given below.

Synthesis Example-1 Dimethyl terephthalate 38 parts, 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene 35 parts, ethylene glycol
Using 27 parts as a raw material and 0.042 part of calcium acetate as a catalyst, these were put into a reaction tank and gradually heated from 190 ° C. to 230 ° C. to carry out a transesterification reaction while stirring. After extracting a predetermined amount of methanol out of the system, 0.012 parts of germanium oxide which is a polymerization catalyst and 0.033 part of trimethyl phosphate are added to prevent coloring, and gradually heated and depressurized to generate. While removing ethylene glycol, heating tank temperature is 280 ° C, vacuum degree is 1 Tor
reach below r. While maintaining this condition, waiting for the increase in viscosity, when the torque applied to the stirrer reached a predetermined value, the reaction was terminated and the reaction product was extruded into water to obtain pellets. The obtained copolymer had an intrinsic viscosity of 0.55 and a glass transition temperature of 124 ° C. The constituent unit derived from the dihydroxy compound was contained in 15.7% in the total glycol component of the pellet.

Synthesis Example-2 The raw material composition was dimethyl terephthalate 26 parts, 9,9-bis- (4-hydroxyethoxyphenyl) -fluorene 56 parts, ethylene glycol 18 parts, calcium acetate 0.028 parts, germanium oxide 0.009 parts. , Trimethyl phosphate was changed to 0.022 part, and the steps were carried out in the same manner as in Synthesis Example-1 to obtain pellets. The obtained copolymer had an intrinsic viscosity of 0.43 and a glass transition temperature of 150 ° C. The constituent unit derived from the dihydroxy compound was contained in the total glycol component of the pellet in an amount of 31 mol%.

Specific examples of the polyester resin of the present invention are shown below, but the present invention is not limited to these.

[0030]

[Chemical 6]

By using the polyester resin of the present invention, good mechanical properties can be achieved without deteriorating the electrophotographic properties. That is, even if the image formation is repeated, the amount of film thickness loss is small and the resistance to abrasion is large.

Further, the polyester resin of the present invention can be prepared by using an ordinary solvent such as tetrahydrofuran, dioxane,
It has high solubility in cyclohexanone, benzene, xylene, monochlorobenzene or dichloromethane, dichlorobenzene or mixtures thereof, and there is no problem of pot life deterioration due to gelation of the solution. It also has good properties such as stability.

In the present invention, the polyester resin of the present invention may have two or more kinds of copolymerization components having the structure represented by the general formula (1), and in the present invention,
Two or more kinds of the polyester resin of the present invention may be mixed and used, and the polyester resin of the present invention may be mixed and used with another resin. Examples of such other resin include polyester resin, acrylic resin, polyethylene resin, polypropylene resin, polyvinylcarbazole resin, phenoxy resin, polycarbonate resin, polyvinyl butyral resin, polyethylene resin, polyvinyl acetate resin, polysulfone resin, polyacrylate resin and vinylidene acrylonitrile chloride. Examples thereof include copolymer resins.

The present invention, and more particularly, the electrophotographic photoreceptor will be described in detail below.

The polyester resin of the present invention is contained in the surface layer of the electrophotographic photoreceptor, and the surface layer may be a photosensitive layer or a surface protective layer provided on the photosensitive layer. .

Even if the photosensitive layer is a so-called single layer type in which the charge generating substance and the charge transporting substance are contained in the same layer, the function is separated into the charge generating layer containing the charge generating substance and the charge transporting layer containing the charge transporting substance. A so-called laminated type may be used.

The charge generating layer can be obtained by applying and drying a liquid dispersed in a binder resin for the charge generating substance. Examples of the charge generating substance include azo pigments such as Sudan Red and Diane Blue, pyrenequinone, and anthanthrone. Examples thereof include quinone pigments, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, azulenium pigments, and phthalocyanine pigments such as titanyl phthalocyanine.

As the binder resin, at least the polyester resin of the present invention is used when the charge generation layer is the surface layer, but when the charge generation layer is not the surface layer, another resin is used without using the polyester resin of the present invention. You can Such other resins are the same as those described above.

The weight ratio of the charge generating substance to the binder resin is preferably 1: 5 to 5: 1, and more preferably 1: 2 to 3: 1. The thickness of the charge generation layer is preferably 5 μm or less, and particularly 0.0
5 to 2 μm is preferable.

The charge-transporting substance contained in the charge-transporting layer is a polycyclic aromatic compound such as bisphenylene, anthracene, pyrene or phenanthrene, a nitrogen-containing cyclic compound such as indole, carbazole, oxadiazole or pyrazoline, or a hydrazone compound. , Styryl compounds, triarylamine compounds and their derivatives, and mixtures thereof.

Generally, the charge-transporting substance has a poor film-forming property, so that it is used by dissolving it in an appropriate binder resin. As such a resin, when the charge transport layer is the surface layer of the photoreceptor, the polyester resin of the present invention is used, but when it is not the surface layer, another resin can be used without using the polyester resin of the present invention. Such other resins are the same as those described above.

The charge transport layer is formed by dissolving the charge transport substance and the binder resin in a suitable solvent, and coating and drying the solution. The mixing ratio of the charge transport substance and the binder resin is preferably 3: 1 to 1: 3 by weight ratio, and particularly 2:
1 to 1: 2 is preferable. The thickness of the charge transport layer is 5 to
40 μm, particularly 10 to 30 μm is preferable.

When the photoreceptor is a single layer type, it can be obtained by coating and drying a solution in which the above-mentioned charge generating substance and charge transporting substance are dispersed and dissolved in a binder resin.

The thickness of the photosensitive layer is preferably 5 to 50 μm,
Particularly, 10 to 40 μm is preferable.

Further, in the present invention, a surface protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer from external adverse mechanical, chemical or electrical effects. This protective layer contains at least the polyester resin of the present invention, but may further contain another resin. Such other resins are the same as those described above. Further, the surface protective layer may be made of a resin alone, or may be added with the above-mentioned charge transport substance or a conductive substance such as conductive powder for the purpose of lowering the residual potential. Examples of the conductive powder include metal powder such as aluminum, copper, nickel and silver, scaly metal powder and metal short fiber, conductive metal oxide such as antimony oxide, indium oxide and tin oxide, polypyrrole and polyaniline. Polymer conductive agents such as polymer electrolytes, carbon black, carbon fibers, graphite powders, organic and inorganic electrolytes, or conductive powders whose surfaces are coated with these conductive substances. The film thickness of the protective layer is determined in consideration of electrophotographic characteristics and durability, but 0.2 to 1.5 μm
Is preferable, and 0.5 to 15 μm is particularly preferable.

In the present invention, an undercoat layer having both a barrier function and an adhesive resin may be provided between the photosensitive layers of the conductive support.

Materials for the undercoat layer include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin polyamides (nylon 6, nylon 66, nylon 61).
0, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide and the like. The thickness of the undercoat layer is preferably 0.1 to 10 μm, particularly preferably 0.1 to 5 μm.

In the present invention, further, a coating is provided between the support and the undercoat layer for compensating for surface defects of the support, and interference fringes which become a problem particularly when the image input is laser light. It is possible to provide a conductive layer for the purpose of preventing the occurrence of This conductive layer is carbon black,
It can be formed by coating and drying a solution in which a conductive powder such as metal particles or metal oxide particles is dispersed in a suitable binder resin. The thickness of the conductive layer is preferably 5 to 40 μm, and particularly preferably 10 to 30 μm.

The various layers described above can be applied by a coating method such as a dipping method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method or a beam coating method.

The conductive support used in the present invention is one in which the support itself has conductivity, such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium and Gold, platinum, or the like can be used, but in addition, aluminum, aluminum alloy, indium oxide, tin oxide, plastic, paper, or the like having a conductive layer obtained by vacuum evaporation of an indium oxide-tin oxide alloy, or conductive Examples of the support include a support in which plastic particles are impregnated with plastic particles or paper, and a plastic having a conductive polymer.

The shape of the support may be drum-shaped, sheet-shaped, or belt-shaped, and is preferably a shape most suitable for the electrophotographic apparatus to which it is applied.

The image holding member of the present invention can be applied to general electrophotographic apparatuses such as copying machines, laser printers, LED printers and liquid crystal shutter type printers. It can be widely applied to devices such as light printing, plate making, and facsimile.

FIG. 1 shows a schematic structural example of an image forming apparatus having an image holding member of the present invention.

In FIG. 1, reference numeral 10 denotes a photosensitive drum which is an image bearing member, which is formed by coating an OPC photosensitive member on the drum and is grounded and rotated clockwise. Reference numeral 12 denotes a charger, which applies a uniform charge of VH to the peripheral surface of the photosensitive drum 10 by corona discharge. Prior to charging by the charger 12,
In order to eliminate the history of the photoconductor until the previous printing, the peripheral surface of the photoconductor may be erased by performing exposure by the PCL 11 using a light emitting diode or the like. .

After uniformly charging the photosensitive member, the image exposing means 13 performs image exposure based on the image signal. The image exposure means 13 in this figure is one in which an optical path is bent by a reflection mirror 132 through a polygon mirror 131, an f.theta. The image exposure means for forming a latent image by scanning) has slit exposure,
Laser exposure, LED exposure, etc. are appropriately selected.

The electrostatic latent image is then developed by the developing device 14. Here, on the periphery of the photoconductor drum 10, there is provided a developing device 14 in which a developer including toner such as yellow (Y), magenta (M), cyan (C), black (K) and a carrier is incorporated. First, the developing sleeve for the first-color developing rotates with the magnet built in and holding the developer.
By 141. The developer consists of a carrier in which ferrite is used as a core and is coated with an insulating resin around it, and a toner whose main component is polyester and pigments according to the color and charge control agents, silica, titanium oxide, etc. are added. The developing agent is developed by the layer forming means 14
1 is regulated to a layer thickness of 100 to 600 μm (developer) and is conveyed to the developing area.
Development is performed by applying a DC or AC bias potential.

In the color image formation, after the visualization of the first color is completed, the process for forming the second color image is started, and the scorotron charger 12 performs uniform charging again, and the latent image by the second color image data is obtained. An image is formed by the image exposure means 13. An image forming process similar to that for the second color is performed for the third and fourth colors, and a visible image of four colors is formed on the peripheral surface of the photosensitive drum 10.

On the other hand, in the monochrome electrophotographic apparatus, the developing device 14
Is composed of one kind of black toner, and an image can be formed by one development.

The recording paper P is temporarily stopped, and when the transfer timing is adjusted, it is fed to the transfer area by the rotation operation of the paper feed roller 17.

In the transfer area, the transfer roller 18 is pressed against the peripheral surface of the photosensitive drum 10 in synchronization with the transfer timing.
The supplied recording paper P is sandwiched and the multicolor image is transferred at once.

Next, the recording paper P is discharged at almost the same time by the separating brush 19 which is brought into a pressure contact state, separated by the peripheral surface of the photoconductor drum 10 and conveyed to the fixing device 20, and the heat roller 201.
The toner is fused by heating and pressurizing the pressure roller 202, and then the toner is ejected to the outside of the apparatus through the paper ejection roller 21. The transfer roller 18 and the separation brush 19 are withdrawn from the peripheral surface of the photosensitive drum 10 after the recording paper P has passed and are ready for the next toner image formation.

On the other hand, the photosensitive drum 10 from which the recording paper P is separated
Removes and cleans the residual toner by pressing the blade 221 of the cleaning device 22, and again receives the charge removal by the PCL 11 and the charge by the charger 12 to start the next image forming process. When superimposing a color image on the photoconductor, the blade 221 moves immediately after cleaning the photoconductor surface and retracts from the peripheral surface of the photoconductor drum 10.

Reference numeral 30 is a removable cartridge in which the image holding member, the charging means, the developing means and the cleaning means are integrated.

As a uniform charging means 12 for the photosensitive drum 10, a corona charging device is generally widely used. Further, the transfer roller 18 and corona transfer means are generally widely used. The electrophotographic apparatus is configured by integrally combining a plurality of constituent elements such as the photoconductor, the developing unit, and the cleaning unit described above as an apparatus unit, and the unit is configured to be detachable from the apparatus main body. May be. For example, at least one of charging means, developing means and cleaning means
Unit together with the photoconductor to form a unit,
A single unit that is detachable from the apparatus body may be used, and the unit may be detachable by using a guide means such as a rail of the apparatus body. At this time, charging means and / or
Alternatively, it may be configured with a developing means.

When the electrophotographic apparatus is used as a copying machine or a printer, the image exposing means irradiates the photoconductor with reflected light or transmitted light from the original document, or a sensor reads the original document to convert it into a signal. According to the above, the laser beam is scanned, the LED array is driven, or the liquid crystal shutter array is driven to irradiate the photoconductor with light.

When used as a printer for a facsimile, the image exposure means 13 provides exposure for printing received data.

[0067]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 Preparation of Sample 1 30 g of polyamide resin CM-8000 (manufactured by Toray Industries, Inc.) was placed in a mixed solvent of 900 ml of methanol and 100 ml of 1-butanol, and heated and dissolved at 50 ° C. This solution was applied onto an aluminum drum substrate having an outer diameter of 80 mm by dip coating to form an intermediate layer having a film thickness of 0.5 μm.

Next, 5 g of the polyester resin Byron 200 (manufactured by Toyobo Co., Ltd.) was dissolved in 1000 ml of 1,2-dichloroethane, and 10 g of "Chemical formula 7" shown below as a charge generating substance was dissolved in the solution.
Was added, and the mixture was stirred with a sand mill for 20 hours for uniform mixing. The intermediate layer was applied by dip coating to form a charge generation layer having a thickness of 0.5 μm.

[0070]

[Chemical 7]

Next, 150 g of the following exemplified compound CTM1-1 as a charge transport material and a charge transport layer binder were used:
150 g of polycarbonate resin Iupilon Z-200 (manufactured by Mitsubishi Gas Chemical Co., Inc.) having a viscosity average molecular weight of 20,000 was dissolved in 1000 ml of 1,2-dichloroethane. This solution was applied on the charge generation layer by dip coating, and then dried at 100 ° C. for 60 minutes to form a lower charge transport layer having an average film thickness of 25 μm.

25 g of the above-exemplified compound CTM1-1 as a charge transport substance and 25 g of the polyester resin of Synthesis Example-1 as a binder were dissolved in 600 ml of 1,2-dichloroethane. This liquid was applied onto the charge transport layer by a circular amount control type coating machine. After drying at 100 ° C. for 60 minutes, an upper charge transport layer having an average film thickness of 5 μm was formed.

Furthermore, the coating solution containing the polyester resin of the present invention was stored at room temperature for 30 days, and the transparency and the spectrophotometer measurement of this solution showed almost no change in the transparency during storage. It was found that the coating solution has excellent storability.

Preparation of Sample 2 Same as Sample 1 except that the binder of the outermost surface layer of Sample 1 was changed to the polyester resin of Synthesis Example 2.

Preparation of Sample 3 The binder of the outermost surface layer of Sample 1 was made to have a viscosity average molecular weight of 20,000.
Sample I was the same as Sample 1 except that it was changed to Polycarbonate Iupilon Z-200.

[0076]

Embedded image

The above photoreceptor was attached to Konica U-Bix 4145 (manufactured by Konica Corp.) having a process of charging, exposing, developing, transferring and cleaning, and an image durability test of 200,000 copies was conducted. The results are shown in Table 1.

Amount of Depletion of Film Thickness The uniform film thickness portion of the photoconductor is measured at 10 points at random, and the average value thereof is taken as the film thickness of the photoconductor. Film thickness meter EDDY 506C (H
ELMUT FISCHER GMBHTCO) was used to measure the film thickness after the first time and after 200,000 copies, and the difference was defined as the amount of film thickness loss.

Potential change amount Black paper voltage (V _B ) after the first durability test and 200,000 copies
And the white paper potential (V _W ) were measured by a surface electrometer and the difference between them was defined as ΔV _B and ΔV _W.

Image Evaluation Image samples after the 200,000 endurance test were examined for image defects such as white lines and black lines in a halftone image.

[0081]

[Table 1]

It can be seen from Table 1 that the sample using the image carrier of the present invention and the sample 2 have improved mechanical properties and electrical properties of the image bearing member as compared with the sample 3 (comparative).

Example 2 Preparation of Sample 4 Same as Sample 1 except that the substrate of Sample 1 was changed to an aluminum drum having an outer diameter of 100 mm and the charge generation layer was changed as follows.

That is, 9 g of silicon-modified butyral resin X-41-1221MP (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a binder in the charge generation layer.
1,4-butanediol 4 g, tertiary butyl acetate 800 g and 4-methoxy-4-methyl-2-pentanone 2
In an X-ray diffraction diagram using CuKα characteristic X-ray as a charge generating substance, it was dissolved in 00g and the Bragg angle (2θ ± 2
0.2 ° C) has a maximum peak at 27.3 °, and other peaks are 9.5 °,
Oxytitanium phthalocyanine having at least one peak at 9.7 °, 11.6 °, 15.0 °, 24.1 °, etc. was added, and then stirred and dispersed in a sand mill for 10 hours to prepare a coating solution. A dry film thickness of 0.3 μm was formed on the intermediate layer to form a charge generation layer.

Preparation of Sample 5 Same as Sample 4 except that the binder of the outermost surface layer of Sample 4 was changed to the polyester resin of Synthesis Example 2.

Preparation of sample 6 (comparative) The binder of the outermost surface layer of sample 4 was made to have a viscosity average molecular weight of 20,000.
Sample I was the same as Sample 4, except that the polycarbonate Iupilon Z-200 was used.

The samples 4, 5 and 6 were charged, exposed, developed,
It was attached to a color printer LP-7010 (manufactured by Konica Corporation) having a transfer and cleaning process, and an image durability test of 100,000 prints was performed. The results are shown in Table 2.

The method for evaluating the amount of film thickness loss was the same as in Example-1.

To evaluate the potential change amount, the solid white potential V _H and the solid black potential V _L are measured, the potential change after the first printing and 100,000 printing is measured with a surface electrometer, and the difference is ΔV _H.
And ΔV _L.

Image Evaluation The image samples after the 100,000 printer durability test were examined for image defects such as streak defects in halftone images.

[0091]

[Table 2]

It can be seen from Table 2 that the image support of the present invention has improved mechanical properties and electrical properties as compared with the comparative image support, even in the evaluation by LP-7010 color printer.

[0093]

As described above, according to the present invention, an image holding member having excellent mechanical characteristics, electrical characteristics, image forming characteristics and high productivity, and an image forming method and apparatus having the image holding member. You get units.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration example of an image forming apparatus having an image holding member of the present invention.

[Explanation of symbols]

 10 Photoreceptor drum 12 Charger 13 Image exposure unit 14 Developer

Claims (6)

[Claims] 1. An image holding member having a plurality of resin layers on a conductive support, wherein the surface layer contains a polyester resin having a structural unit represented by the following general formula (1). Element. Embedded image (R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ ,
R ₄ and R ₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ) 2. The polyester resin comprises an aromatic dicarboxylic acid or a diester derivative thereof and 2 to 4 carbon atoms.
Of the aliphatic glycol and a dihydroxy compound represented by the following general formula (2), and a structural unit derived from the dihydroxy compound represented by the general formula (2) is contained in all glycol components of the polyester resin. The image holding member according to claim 1, which is a polyester resin containing 5 mol% or more. Embedded image (R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ ,
R ₄ and R ₅ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ) 3. The image bearing according to claim 1, wherein the plurality of resin layers are composed of at least two layers of an undercoat layer, an intermediate layer, a plurality of photosensitive layers and a protective layer. Element. 4. A conductive support having at least a charge generation layer and a charge transport layer composed of a plurality of layers thereon, and the uppermost layer of the charge transport layer is a surface layer of the image holding member.
The image holding member according to claim 2 or 3. 5. A step of forming an electrostatic latent image on an image holding member comprising a polyester resin having a constitutional unit represented by the general formula (1) contained in a surface layer on a conductive support, It has a developing step of developing the latent image with toner, a transferring step of transferring the visualized toner image to a recording material, and a step of cleaning the toner remaining on the image holding member after the transfer. Image forming method. 6. An apparatus unit having an image holding member, a charging member, a developing unit and a cleaning unit, wherein the image holding member is the image holding member according to claim 1. An apparatus unit, which integrally supports the cleaning means and the cleaning means, and is detachable from the apparatus body.